A linear coupling between a scalar field and the Gauss–Bonnet invariant is the only known interaction term between a scalar and the metric that: respects shift symmetry; does not lead to higher order equations; inevitably introduces black hole hair in asymptotically flat, 4-dimensional spacetimes. I will consider a scalar-tensor theory of gravity that includes such a coupling and present...
Higher derivative extensions of Einstein gravity are important within the string theory approach to gravity and as alternative and effective theories of gravity.
We consider two numerical black-hole solution: by P. Kanti, et. al. in the Einstein-dilaton-Gauss-Bonnet theory [Phys.Rev. D54 (1996) 5049-5058] and
the one by H. L\"u, A. Perkins, C. Pope, K. Stelle [Phys.Rev.Lett. 114 (2015),...
We analyze spherically symmetric black holes in the general Lovelock gravity for different asymptotics (flat, dS, AdS). We find numerically the metric coefficients of the physically relevant branch of the solutions and the corresponding effective potentials for the gravitational perturbations. We also perform a comprehensive analysis of the eikonal instabilities of the black holes.
